Bedforms occur in many depositional systems, and can be influenced by unidirectional, oscillatory, or combined flows. In this paper, Perillo et al. collected experimental data under a wide range of unidirectional, oscillatory and combined flows to address range of unexplored flow conditions (strong unidirectional flows and intermediate oscillation periods) where the bedform geometry, and hence consequent sedimentary structures, have not been explored. Under these flow conditions, ten distinctive bedform states are identified, and the planform and cross-sectional geometry are described. This new nomenclature unifies past research on bedforms in both unidirectional and oscillatory flows, and thus presents a new synopsis of bedforms developed under such flows. This new data and analysis allows proposition of a new unified phase diagram for combined flows.
A new phase diagram for combined-flow bedforms by Mauricio M. Perillo, James L. Best, and Marcelo H. Garcia